Breath holds and CO₂ tolerance
The urge to breathe is not oxygen running out — it is carbon dioxide building up, and that tolerance is trainable. Never practise breath holds in or near water: hyperventilating before a hold causes shallow-water blackout, which kills experienced swimmers without warning. Always sit or lie down.
Practise calm breathing →Wim Hof Method →Buteyko method →
Breathe is a free guided breathing and meditation web app — no download, works in your browser. Enable JavaScript for the interactive guided session.